- Fix invalid polymer light array access originating from game's cleanup

callback 'G_Polymer_UnInit'.
- In astub.c, reset spritelightid to -1 when nulling the spritelightptr of
  a sprite  (no crashes observed, just precaution)
- In sdlayer.c, catch SIGILLs with our signal handler too, since illegal
  instructions are what the instrumented debug builds will execute when
  attempting to carry out an undefined (per C) operation.

git-svn-id: https://svn.eduke32.com/eduke32@2169 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/build/src/sdlayer.c

@@ -319,6 +319,7 @@ int32_t initsystem(void)
     }
 
     signal(SIGSEGV, sighandler);
+    signal(SIGILL, sighandler);  /* clang -fcatch-undefined-behavior uses an ill. insn */
     signal(SIGABRT, sighandler);
     signal(SIGFPE, sighandler);
 

polymer/eduke32/source/actors.c

@@ -487,6 +487,7 @@ int32_t block_deletesprite = 0;
 #ifdef POLYMER
 static void A_DeletePolymerLight(int32_t s)
 {
+    if (actor[s].lightId >= 0)
         polymer_deletelight(actor[s].lightId);
     actor[s].lightId = -1;
     actor[s].lightptr = NULL;

polymer/eduke32/source/astub.c

@@ -315,6 +315,7 @@ static void DeletePolymerLights(void)
         if (spritelightptr[i] != NULL)
         {
             polymer_deletelight(spritelightid[i]);
+            spritelightid[i] = -1;
             spritelightptr[i] = NULL;
         }
 }